Cat Anatomy & Physiology Jeremy Lawson March 11, 2025

Interested about those sharp little tools your cat uses for climbing, hunting, and occasionally shredding your furniture?

This blog covers everything about cat claws – from what they’re made of to how they work.

We’ll examine their unique structure, how cats retract them, and why this ability is so important.

You’ll learn about proper claw care and common problems to watch for, and we’ll clear up some myths about cat claws.

By the end, you will have a new appreciation for these remarkable features essential to your cat’s health and happiness.

What Are Cat Claws Made Of?

Composition (Keratin)

Cat claws are made of a protein called keratin. This is the same material found in human hair and skin.

Keratin makes cat claws both strong and flexible. The outer part is hard and sharp, while the inside has softer tissue with blood vessels and nerves.

Comparison to Human Nails

Cat claws and human nails share the same basic material – keratin. However, cat claws are curved, sharper, and grow in layers.

Human nails are flat, grow as single pieces, and don’t shed. Cats can pull their claws in and out, but humans can’t move their nails this way.

Why Cats Shed Claw Sheaths

Cats shed the outer layers of their claws because new growth pushes out from underneath. This natural process keeps their claws sharp and healthy.

You might find these thin, clear sheaths around your home. Scratching posts helps cats remove these old layers more easily.

Anatomy of a Cat’s Claw

Cat claws have a structure that helps them function as essential tools for climbing, hunting, and self-defense. Let’s look at the key parts that make up a cat’s claw:

The Quick

The “quick”—the living portion containing blood vessels and nerves—is at the center of each claw.

This sensitive pink tissue provides nutrients to the growing claw and sends pain signals if injured. The quick doesn’t extend to the tip, which allows cats to wear down or shed the ends without pain.

Claw Layers

Cat claws grow in multiple layers, similar to an onion:

• The inner layer contains the quick and is soft and flexible
• Middle layers provide strength and support
• The outer layer forms a hard, sharp surface
• New growth pushes from the base, causing older layers to move outward
• The oldest outer layers shed regularly as thin, clear sheaths

Blood Supply System

Blood vessels run through the claw quickly, delivering oxygen and essential nutrients to support its growth and health.

This vascular network is connected to the cat’s circulatory system through the toe bone, ensuring continuous nourishment and repair.

When examined under bright light, the quick appears as a pink area inside the claw.

However, as cats age, the efficiency of this blood supply may decrease, leading to more brittle claws that require extra care.

Attachment Point

The claw connects firmly to the last bone in the cat’s toe (the third phalanx) through strong connective tissues.

This secure attachment works with specialized muscles and tendons to give cats precise control over claw extension and retraction.

How Do Cat Claws Retract and Extend?

Cat claws work through a special system of muscles, tendons, and ligaments, allowing cats to show or hide their claws as needed. This setup is both simple and complex at the same time.

The main parts include:

• Two tiny but strong tendons that connect to each toe
• Small muscles in the paw that pull these tendons
• Elastic ligaments that act like rubber bands
• A special groove in the last toe bone where the claw rests

Step-by-Step Breakdown

1. Resting State: When a cat is relaxed, their claws stay tucked away. Elastic ligaments naturally hold the claw in this position – no muscle effort is needed.
2. Extending: When a cat wants to use its claws, it tightens the muscles on top of the paw. These muscles pull tendons that rotate the last toe bone forward, pushing the claw outward.
3. Active Control: Cats can control each claw separately for climbing or grabbing. This fine control comes from the small, precise muscles in their paws.
4. Returning to Hidden: When the cat relaxes its muscles, the elastic ligaments pull the claw back into its resting spot. This happens automatically without the cat needing to think about it.

This system keeps claws sharp by storing them safely when not in use, protecting them from wearing down during normal walking.

Why Do Cats Have Retractable Claws?

Cats have retractable claws for several key reasons. During hunting, these sharp tools allow cats to grab and hold prey with great accuracy.

When climbing, cats use their claws as hooks to grip tree bark, carpet, or other surfaces, helping them reach high spots safely.

For self-defense, a cat can quickly show its claws to scare away threats or fight if needed.

Cats also use their claws for grooming and scratching, which helps remove dead outer layers and keeps their claws healthy and sharp.

This special claw system helps cats survive and thrive in many different settings.

Myth-Buster: Do Claws “Disappear” When Retracted?

No, cat claws don’t truly disappear when pulled in.

They fold back into a protective skin pocket above the toe pad.

This keeps them sharp by preventing ground contact during normal walking. Many cats’ claw tips can still be seen even when fully retracted.

Dewclaws and Polydactyl Cats

What is a Dewclaw?

A dewclaw is a small, extra toe located slightly higher on a cat’s front paws. Unlike the other claws, it does not touch the ground when a cat walks.

It is attached to the cat’s leg by bone and muscle, making it functional for gripping objects, climbing, and holding onto prey. However, some cats may have reduced or non-functional dewclaws.

Why Do Some Cats Have Extra Toes?

Some cats are born with extra toes due to a genetic mutation called polydactyly. Polydactyl cats can have six or more on each paw instead of the usual five toes on the front paws and four on the back.

This condition is harmless and sometimes gives the cat better balance and grip.

Polydactyl cats are often called “Hemingway cats” because author Ernest Hemingway had a colony of them at his home in Key West, Florida.

How to Care for Your Cat’s Claws

Importance of Regular Trimming

Your cat needs claw care. Long claws can cause problems. They may get stuck in carpet or furniture. This hurts your cat.

Regular trimming keeps claws at a good length. It stops painful breaks. It also reduces damage to your home.

Most cats need trimming every 2-3 weeks. Indoor cats often need more frequent trims than outdoor cats.

Signs of Overgrown or Unhealthy Claws

Watch for these warning signs. Claws that curve into a complete circle. Limping or strange walking. Your cat is pulling at their paws.

Claws that look thick or misshapen, broken or split claws, blood spots on floors or furniture, constant paw licking, and pain when you touch the paws are signs that your cat needs help immediately.

Best Tools for Trimming

Get the right tools for the job. Small scissors-style clippers work well, and some people like guillotine-style trimmers. Keep them sharp for clean cuts.

A good scratching post helps, too. Sisal rope posts last a long time.

Cardboard scratchers are cheaper but need replacing. Some cats like tall posts. Others prefer flat scratchers.

Try different types to see what your cat likes. A file can smooth rough edges after trimming.

Common Misconceptions About Cat Claws

Cat claws don’t fully retract inside the paw—they fold back into a skin pocket above the toe pad.

Yes, a cat’s claws can get stuck in fabric, carpet, or other materials, which can be painful and sometimes dangerous.

Not all cats need trimming; outdoor cats naturally wear down their claws, while indoor cats often need regular trimming to prevent overgrowth and related problems.

Conclusion

Cat claws are marvels of natural design that serve many purposes in feline life.

These keratin structures help cats hunt, climb, defend themselves, and maintain health through scratching behaviors.

Understanding how claws grow, retract, and function helps cat owners provide better care and recognize when something isn’t right.

While outdoor cats naturally wear down their claws, indoor cats need our help with regular trimming and appropriate scratching surfaces.

By respecting and properly caring for your cat’s claws, you support their physical and mental well-being while protecting your home from unnecessary damage.

Frequently Asked Questions

What Does an Unhealthy Cat Claw Look Like?

Unhealthy cat claws appear thick rather than thin and sharp. This thickening might point to health issues that need a vet’s attention.

Is It Cruel to Declaw a Cat?

Yes. The AAFP opposes this because it causes pain and infection risks and can lead to ongoing behavior and movement problems.

What is the Hard Thing Growing Out of My Cat’s Paw Pad?

It’s a cutaneous horn, similar to a callous. This harmless growth forms where the paw regularly rubs against surfaces.